I am investigating controlling stepper motors with the A-board.
I know that you can buy a stepper motor controller IC, but I want to do things the hard way
So, now I am trying to control the stepper motor using a TTL 74194 shift counter, a hex inverter (for direction control) and a darlington transistor array. (don't be impressed! - I am just following the instructions in a book!)
Amazingly this seems to work, however, the book recommends using a hex buffer before the darlington transistor array to (and i quote....)
'..protect the translator circuit from the motor's supply voltage in the event of a transistor-to-base breakdown.'
Anyway I tried connecting up a hex buffer (sn7407n) and now things don't work.
I'm sure that this is a mistake in my circuit (i'm a electronics beginner) but before I try again, i wanted to ask.... is the buffer needed?? I notice on the 'Unipolar Stepper Motor' tutorial, there is no buffer being used. What do you guys recommend??